ABSTRACT
Let T = T m be the term algebra generated by the variables in X under the operations A ,V and -i . Let R m be the relation of interdeducibility w ith respect to L M , and let A m be the class of all models of R m; the algebras in Am I call m -algebras. There holds the
THEOREM l m Am is the class of all algebras A = < u (A ), D ,n ,u , - > w ith a distinguished element e in A which, in addition to (a mp),
(amo) aD -b = bD-a.
